This section provides background information related to the present disclosure which is not necessarily prior art.
Electrical systems within vehicles, such as hybrid, electric, and fuel cell vehicles, have advanced in complexity and power usage. Such vehicles can include an electric motor in combination with a battery power source. The battery can power the vehicle alone or can work in conjunction with another power source, such as an internal combustion engine.
High power output and large capacity batteries can be used as a battery power source; e.g., nickel-metal hydride or lithium-ion polymer batteries. A number of battery cells can be connected in series or parallel with each other so as to construct a larger battery assembly. The battery cells can be packaged together with various mechanical and electrical couplings between the battery cells to form the assembly. Various battery cells types, shapes, and sizes exist, including flat, curved or rounded, and cylindrical cells. Battery cells can include prismatic batteries or pouch-shaped batteries that can be placed in a stacked relationship to reduce space and overall size of the assembly. Such battery cells can exhibit changes in one or more dimensions during charging and discharging and over their lifetime, where the battery cells can expand and contract.
Heat can be generated by the battery cells during charging and discharging processes. Accumulation of heat in the battery assembly can impact the performance of the battery cells. Consequently, a cooling system can be provided to maintain a particular operating temperature or temperature range. Such cooling systems can include fluid heat exchangers that operate by moving air over the cells and/or through the use of liquid cooling systems. These cooling systems, however, can present high manufacturing and maintenance costs, and issues may arise due to the relatively high number of parts, including seals and joints needed between cooling system components. In certain cases, it may also be necessary to insulate a cooling fluid from the battery cells and insulate the battery cells from each other.